Probiotics Explained

You may not know it, but you’re living in peaceful coexistence with more than 500 species of bacteria in your gut. Taking a probiotic to boost their numbers has long been known to help ward off various complaints. Now, there’s emerging evidence that these tiny critters are more important for our health than we ever imagined.

From HealthSmart Magazine

Probiotics – what are they?

Probiotics were fi rst identifi ed more than 100 years ago, when Russian scientist and Nobel laureate Elie Metchnikoff observed that Belgian peasants who ate a lot of yoghurt lived long and healthy lives. Probiotics contain strains of yeast or bacteria that live naturally in our intestines. They are available in capsules, powder, fermented milks or yoghurts. We each have a unique profi le of gut fl ora, as individual as a fi ngerprint, with which we're stuck for life. Their numbers can be depleted by stress, drugs, alcohol and especially when we take antibiotics. They'll come back eventually – but taking a supplementary dose may bring them back to healthy levels faster and ward off infection or diarrhoea.

What do probiotics do for our health?

Taking extra probiotics can help in a number of ways. As well as boosting the number of "good" bacteria in the gut, they also have direct effects on the cells lining the intestine and switch off the infl ammatory process. Some affect the immune system by changing the way the white cells and antibodies work. According to alternative medicine – though not proven scientifi cally – an imbalance in gut fl ora can lead to a condition called "leaky gut syndrome" in which large molecules cross the gut wall and spark an immune response, leading to allergic disease. "The three central messages in naturopathy are ‘treat the gut, treat the gut, treat the gut'," says Pam Stone, a practising naturopath and director of education at natural healthcare company Blackmores.

What evidence is there that probiotics work?

A paper published recently in the Medical Journal of Australia confirmed probiotics are benefi cial for several forms of diarrhoea, including infectious types, especially rotavirus, and diarrhoea associated with antibiotic use. Probiotics are also believed to be helpful for bowel disorders such as irritable bowel syndrome and ulcerative colitis. Research is underway into their probable beneficial effects on other diseases including Crohn's disease, pouchitis and necrotising enterocolitis, says Dr Andrew Day, associate professor in the School of Women's and Children's Health at the University of New South Wales. There's also some evidence they make our immune system stronger and benefit such conditions as eczema and possibly asthma. One recent European study found that babies whose mothers took a probiotic during pregnancy had fewer infections, diarrhoea and allergies. Some medics now believe that our depleted levels of “good" gut bacteria – from taking antibiotics and living in a sterile environment – may be in part responsible for the increase in obesity, allergies and other illnesses.

Where can I get probiotics?

The main natural source of probiotics is yoghurt, especially varieties that contain added probiotics, such as Vaalia. Fermented drinks such as Yakult are also a good source. Some foods have added probiotics, including yoghurt and bread. In Europe there are even probiotic sausages, and in the US, probiotic ice-cream. If you're after a really big dose, for example if you're taking a course of antibiotics, you can't go past a supplement. Capsule or powdered probiotics are available from health-food shops.

How often should I take them?

Follow the directions on the preparation if you're taking a supplement.

How do I know I'm getting what I'm supposed to be getting?

There are many kinds of probiotics, and you need specifi c strains to treat specifi c disorders (see “Which bugs?" box, above). The problem is that a lot of them die before they reach the part of the intestine where they're needed. As well as making sure you get the right sort of probiotic, you need to know you're getting enough.

We need 100 million to 1000 million live probiotic bacteria a day. Under the Food Standards Code, probiotic drinks and yoghurts must contain at least one million live bacteria per gram, and companies claiming their products contain biologically active ingredients must state the amount in the nutrition information panel. However, there is no standard method for counting the bacteria.

Overseas research has found that some products contain far too few bacteria to be effective. In a 2006 study, consumer group CHOICE tested some leading brands of probiotic yoghurts and drinks, and found that only four products had more than one million live bacteria per gram.

The best advice: stick to brands you believe will have applied the correct quality assurance procedures, choose a health-food shop with a high stock turnover so you know the product is unlikely to be old, and keep your probiotic in the fridge after you get it home.